Water sports are becoming increasingly popular. Costs and physical size constraints can prevent the use of kayaks in a large number of cases and use of surf and sail boards is often prevented due to lack of wind or waves.
A conversion kit to convert a sail or surf board into a water bicycle is described in U.S. Pat. No. 4,511,338 dated Apr. 16, 1985 entitled "Water bicycle and detachable device therefor", inventor Noel Fanelli.
Another conversion kit is described in U.S. Pat. No. 5,377,607 dated Jan. 3, 1995 entitled "Conversion arrangement for sail board with seat", inventor Gerald S. Ross. Still another conversion kit is described in U.S. Pat. No. 4,752,261 dated Jun. 21, 1988 entitled "Auxiliary seat for surf boards", inventor Michael A. Rosello Zoya.
The Fanelli patent describes the use of board encircling straps to secure the conversion kit to the board but otherwise has no relation to a kayak type paddling craft. The Ross patent shows in FIG. 3 the board used as a kayak, however the seat is adjustable but not the foot rest, therefor the seat cannot be conveniently positioned in the region of the buoyant center of the board irrespective of the user's height.
The Zoya patent shows an arrangement in which the distance between the foot rest and seat can be adjusted to suit the height of the user but the kit frame rests flat on the surf board and therefore could not conveniently clear feet anchoring straps and mast anchors normally portruding form the top wall of a sail board. Also, adjustment of the distance between the foot rest and seat is difficult to achieve.